Sound amplifier



Sept. 30,. 1930. a HARFUSON 1,776,902

SOUND AMPLIFIER Original Filed Nov. 29, 1926 2 Sheets-Sheet l ['6 Z k3 INVEINTQR 17 fRcELL 5. HAemso/v ATTORNEYS Se t. 30, 1930. E. B. HARRISON SOUND AMPLIFIER Original Filed Nov. 29, 1926 2 Sheets-Sheet 2 INVENTORI EQCELL B. HARRISON ATTORNEYS diaphragm.

Patented Sept. 30, 1930 UNITED STATES PATENT OFFICE ERCELL B. HARRISON, OF PASADENA, CALIFORNIA, ASSIGNOR TO LOUIS ADOLPH SCHMUCK, OF PASADENA, CALIFORNIA SOUND AMPLIFIER Application filed November 29, 1926, Serial No. 151,492. Renewed February 12, 1930.

My invention relates to sound amplifiers, particularly adapted, although not necessarily, for use as loud speakers in radio receiving apparatus of the character embodied in my co-pending application Serial No. 157,750, filed Dec. 29, 1926. I

It is a purpose of my invention to provide a sound amplifier which is capable of blending and amplifying sound waves emanating from two different sources having different ranges of vibrations whereby bass and treble tones can be separately received, blended and amplified in a manner to secure superior amplification without distortion.

I will describe only one form of sound amplifier embodying my invention and will then point out the novel features thereof 1n claims.

In the accompanying drawings,

Figure 1 is a view showing in vertical section one form of sound amplifier embodying my invention; v

Figure 2 is a view showing the sound outlet end of the amplifier in front elevation;

Figure 3 is a fragmentary vertical sectional view taken at right angles to Figure My invention in its present embodiment, comprises a base designated generally at B and preferably constructed of a dead metal such as white metal. form and is constructed to provide a chamber 15 opening downwardly and adapted to contain a pair of sound reproducing units, one

- for bass tones and the other for treble tones.

The bass tone unit consists ofa diaphragm 16 formed ofspruce veneer or a similar material mounted as shown and operatively connected to the core 17 of an electromagnet 18 in such manner that the core functions to vibrate the The treble tone unit comprises the diaphragm 19 made of mica or duralumin. is operatively connected to'an armature 20 of an electromagnet 21.

The base B is formed with two sound passages 22 and 23 having their lower ends spanned, respectively, by the diaphragms 16 and 19 so that sounds produced by the diaphragms will enter the lower'ends of the passages for conduction upwardly through the base. The upper ends of the passages converge into the lower end of a tapered throat This base is of circular T, preferably constructed of fiber or hard I rubber. Between the upper ends .of the passages 22 and 23 and secured on the base B is a blending reed 24 which may be formed of parchment, spruce veneer or mica and which, as illustrated to advantage in Figure 3, is of tongue-shaped formation with its lower straight edge suitably secured in agroove 25 of the base B.- As shown in Figure 1, the reed tapers in thickness so as to provide a relatively thin free end, the cross sectional contour of the reed bein such as to render it responsive to bass an treble tone vibrations and to thereby effect a blending of the two as they proceed upwardly of the throat T.

The lower end of the throat T has an interfitting connection with the upper end of the base B. At its upper end it is curved laterally to merge into an outlet designated generally at D and made up of a plurality of sound amplifying elements, preferably formed of spruce. In the present instance I have shown the outlet as constructed of a low tone amplifying element E,an intermediate tone amplifying element E, and a high tone amplifying element E The elements E and E are made up of a plurality of panels 26 and 27, respectively, and as shown these panels are arranged to produce an outlet D of conical formation. The element E is likewise made up of a plurality of panels 28 interposed between the elements E and E so as to divide the sound passage formed by the elements E and E The panels 26, 27 and 28 are tapered in thickness from their point of connection with the upper end of the throat T to their free ends in order that they may be capable of vibratory movement to amplify the sound waves passing upwardly from the throat T. The element E because of its construction and location with respect to the throat T functions to amplify tones of the low musical range; the element E amplifying tones of intermediate range; and the element E amplifying tones of the high musical range. It will thus be seen that the outlet D as a unit functions to separately amplify the several group tones of the musical range.

Within the throat T at a point above the 100 29 and 30 arranged one above the other and at that side of the throat correspondin to the passage 22 in order that these diap iragms may function to amplify the low tones passing upwardly from the passage 22. The diaphragms 29 and 30 .are preferably formed of brass and are of disk-shape, and are supported to freely vibrate by means of spring 31 secured to the inner Wall of the threat '1.

In practice, the two sound reproducing units are adapted for association with a radio receiving circuit of the design embodied in my co-pending application hereinbefore referred to in such manner as to separately reproduce the bass and treble sounds or tones as received from the set, the bass sounds .as emanating from the diaphragm 16 travelling upwardly of the passage 22, and the treble sounds as emanating from the diaphragm 19 travelling upwardly of the passage 23. As previously described, the reed 24 functions to blend the bass and treble sounds, ,the diaphragms 29 and 30 intereept in' he bass sounds to the extent of being vibrated therein and in unison therewith so as to amplify such sounds. The amplifying elements E, E and E serve to effect a further amplification of the sounds and separately in respect to the- I they are formed are responsive to certain ranges of vibrations, thereby eifecting ampli fication without distortion.

Although I have herein shown and 1 ing a pair of sound passages therein, sound reproducing units one for each of the passages, said units being independent of each other and correlated with one end of the passages to receive the sounds emanating from said units, a throat of tapered diameter connected to the base so as to be in sound receiving relation to the sound passages, and

' an outlet at the other end of the throat havoutlet in sound receiving relation with respect to the throat having a plurality of sound amplifying elements.

3. A sound amplifier-comprising a base having a pair of sound passages therein,

sound reproducing units one for each of the /'d\e-\ scribed only one form of sound amplifier empassages, a blending" reed associated with sound receiving relation to said passages, and an outlet in sound receiving relation to the throat and having a plurality of sound aniplifying elements.

4. A sound amplifier comprising a throat having a blending reed extending thereinto, sound amplifying diaphragms in the throat,

- and an outlet in sound receiving relation with respect to the throat and composed of a plurality of sound amplifying elements, each of the elements comprising a plurality of panels capable of vibratory movement.

5. In a sound amplifier, an outlet of conical form having a plurality of sound amplifying elements, each of the elements comprising partitions tapered in thickness and of a material capable oi vibratory movement.

6. A sound amplifier comprising a base having a pair of sound passages therein, sound reproducing units one for each of the passages, a throat in sound receiving relation with respect to said passages, a blending reed supported on the base and extending into said throat, a plurality of diaphragms supported in the throat at a point above'said reed and at that side of the throat corresponding to apredetermined sound passage, and an outlet in sound receiving relation to the throat comprising a plurality of amplifying elements each of which is responsive-to sound vibrations of a predetermined frequency.

7. sound amplifier comprising a body having a plurality of sound passages therein, sound reproducing units one for each of the passages, a blending reed associated with the outlet of said passages, a throat in sound re ceiving relation to said passages and an outlet in sound receiving relationto the threat.

8. A sound amplifier comprising a body having a plurality of sound passages therein, sound reproducing units one for each of the passages, a blending reed associated with the outlet of said passages, a threat in sound receiving relation to said passages, sound amplifying diaphragms in the throat, and an outlet in sound receiving relation to the throat.

9. A sound amplifier comprising a body having a plurality of sound passages therein, soundreproducing units one for each of the passages and correlated with the latter ina manner to-receive the sound emanating from the respective unit, each of saidiunits including a diaphragm mounted for vibratory movement independently of the diaphragm of another unit so that the diapihragms will die capable of responding independently of receiving relation to said passages.

1( )'l A sound amplifier comprising a body having aplurality of sound passages therein, sound reproducing units one for each ofthe passages and correlated with the latter in a manner to receive the sound emanating from the respective unit each of said units including a diaphragm mounted for vibratory movement independently of the diaphragms will be capable of responding, inde endently of each other, to sound vibrations of relatively different amplitudes, a throat in sound receiving relation to said passages, a reed in said throat for blending the relatively different sound vibrations emanating from said diaphragms, and an outlet in sound receiving relation to said throat.

11. A sound amplifier comprising means defining a plurality of sound passages, a blending reed associated with'the outlet of the passages, a throat in sound receiving relation to the passages, and sound amplifying diaphragms in the throat.

ERCELL B. HARRISON. 

